I entered to the end in order to beat the ender dragon, and I wanted to burn the ender crystals first, so I used scaffolding blocks in order to reach the top of the tallest towers, before I started to combat him, the ender dragon can throw me fireballs and something, but after destroying all ender crystals, he just started flying around in circles (he was flying so high without getting down). Moreover, I put a high tower of scaffolding blocks in order to reach it almost melee and he didn't attack me, I killed with a crossbow easily.

Note: I'm not sure if the scaffolding block was the real cause, but I suspect about it because mobs apparently can't even pathfind on it (I got aggro of endermen when I was over my scaffolding tower and they didn't tp near me).